1. Field of the Invention
The present invention relates to a gas turbine combustor burning LBTU (low BTU) fuel gases, and especially to a can combustor employed in a small turbogenerator (10 KW), which is integrated by LBTU gas generator. A very strong recirculation zone is generated in the primary zone of the combustor to increase the flame-stabilization capability.
2. Description of the Prior Art
In the recent years, the use of LBTU fuel gas, obtained from biomass, process byproduct, coal, and industrial waste, in gas turbine for electricity generation is of special interest due to the considerations of energy saving and environmental protection. From the economical viewpoint, the above system may be commercialized in the power output range of above few MWs because of high initial capital investment. In addition, an abundant supply and easy access of the raw material for generating LBTU gas is essential for the power plant operation. However, the present invention is focused on the small turbogenerator applications since the generation amount of LBTU gas is small in some places.
One major challenge to overcome in making the very small turbogenerator using LBTU fuel possible is designing a gas turbine combustion system that will burn LBtu gas properly and completely. Most large industrial gas turbines have large combustion chambers to support the complete combustion need of LBTU gas once the fuel delivery and injection system has been modified. As designing the gas turbine combustor burning the LBTU gas under a stringent size constraint, several performance characteristics are emphasized in the present invention. One of the most concerned characteristics is the flame stabilization capability of the combustor.
The primary object of the present invention is to provide a gas turbine combustor burning LBTU fuel gas with high combustion efficiency and stability.
Another object of the present invention is to provide a combustion system matching with a 10 KW turbogenerator originally fueled by diesel fuel. A fuel inlet is designed for supplying the high BTU gas in order to increase of the flamability range and facilitate the engine starting.
A further object of the present invention is to provide a gas turbine combustor which is used the LBTU gas jet to enhance the fuel/air mixing and to facilitate the flame stabilization.
A still object of the present invention is to provide a gas turbine combustor having the advantage of waste processing and environmental protection.
The gas turbine combustor with the aforesaid advantages includes: a combustor outer case having a barrel with a reduced end portion and being enclosed at the outer periphery of the combustor liner, the annular between the outer case cartridge and liner serving as a path for being entered by the reverse flow of a compressed air;
a combustor liner, the front section, middle section and rear section thereof being installed with a row of primary holes, a row of dilution holes, a first row of cooling holes, and a second row of cooling holes; one and portion of the inner liner being installed with a conical of liner for being combined with the base of a radial swirler;
a adjustable swirler formed by a radial swirler base and a swirler angle controller, wherein the radial swirler base serves to seal the distal portion of the combustor and has a hollow structure, after the hollow portion is assembled to the gas inlet, a slit is formed; the swirler is radially installed with guide plates and sealing plates; the swirler angle controller is formed by a pinion and an annular angle controller the inner periphery of which is installed with a linkage for driving the radial swirler in order to adjust the orientation of the blades of the annular angle controller;
a fuel gas nozzle connected to the swirler base by a flange, an inlet for fuel gas with high heating value is installed at the center, an annular flow path for inputting LBTU gas is installed at gas inlet joint, the outlet of the flow path has an inclined design for forming with an inclined fuel gas injection.
After compressed air flows into combustor, it will further flow to the channel through the annular between the outer case and the liner, therefore, the air will first enter into the dilution region and intermediate region and then arrive at the primary region and the frontal section. Thus, the combustor of the present invention is a reverse flow type combustor. After air enters into the front section, it will be further guided by a radial swirler vanes and then generating a strong swirling jet into the combustion chamber. The recirculation zone due to the vortex breakdown of the swirling jet is then formed. To preserve the recirculation zone and enhance the mixing between the fuel and combustion air, the gas inlet for LBTU gas is designed to be inclined. The primary jets emerging from a proper axial position will close the recirculation zone and supply the fresh air for the combustion need of the fuel gas in the primary zone. Consequently, a stable flame stabilization mechanism can be generated under the interaction among the swirling air jet, inclined fuel jet and the primary jets. The dilution jets can mix with high temperature combustion gas from the primary zone and then reduce the combustion gas temperature to a certain level which is acceptable by the turbine section. The main purpose of the intermediate region is to provide a combustion room for complete combustion of the fuel gas. Air streams from the first and second rows of the cooling holes serves to eliminate the hot spots near the outer combustion liner and thus reduce the outlet pattern factors.